In their first public remarks since last week's gala for the Indian prime minister Manmohan Singh, Tareq and Michaele Salahi told NBC television's Today show that they have documents proving they were authorised to attend. They said they will make the documents public once the US secret service has completed its investigation into the incident.

"We were invited, not crashers," Michaele said. "There isn't anyone that would have the audacity or the poor behaviour to do that."

Tareq said the couple have co-operated with the secret service.

"Our lives have been destroyed," Michaele said. "Everything we worked for."

White House state dinners are the top event of the Washington social calendar. Last week, the Salahis joined hundreds of high-profile figures from politics, the media and Hollywood to fete Singh and the US-India relationship, even shaking Obama's hand.

But no sooner had they arrived than journalists noted they were not on the guest list, despite the White House being among the most highly guarded presidential compounds in the world. White House aides insist the couple were not invited, and the affair has embarrassed the secret service. The couple could face criminal charges in the matter.

The Salahis apparently sought access to the Singh gala through a senior Pentagon official who appears to have an association with their lawyer, the Washington Port reported. The Salahis seemed to believe that Michele Jones had cleared them to attend the White House event. But Jones said in a statement that she never stated or implied that she had tickets for them and told them that she was not empowered to authorise their attendance.

"This wasn't a misunderstanding," White House spokesman Robert Gibbs said. "You don't show up at the White House on a misunderstanding."

Meanwhile, a local Washington television station reported the couple had sneaked into a black-tie fundraising dinner for the Congressional Black Caucus in September. The pair were apparently discovered and escorted out after being photographed with luminaries such as New York congressman Charles Rangel, a prominent liberal, the local Fox television affiliate reported.

On NBC this morning, the Salahis denied that report, saying they had been invited to the dinner through their attorney.